Ohio State University Extension Fact Sheet

Horticulture and Crop Science

2001 Fyffe Court, Columbus, OH 43210-1096

Poison Ivy Identification and Control

HYG-1015-96

Cindy Welyczkowsky
Jane C. Martin

Anyone who has ever experienced the blisters, swelling, and extreme
itching from an unfortunate encounter with poison ivy, learns quickly
to avoid it whenever possible. It grows in non-cultivated sites, such
as along stream banks, roadways, fencerows, and woodlands. It can even
make an appearance in your ornamental shrub or perennial borders.
Therefore, knowing how to identify and control it are the best
defenses against accidental contact.

Identification

The best way to identify poison ivy (Rhus radicans) is by its
characteristic compound leaf consisting of three leaflets. The
leaflets are two to four inches long, dull or glossy green with
pointed tips. The middle leaflet is generally larger than the two
laterals. The margins of the leaflets are variable, appearing
irregularly toothed, lobed, or smooth. The leaves are positioned
alternately on the stems. In contrast, Virginia Creeper, a
non-poisonous vine often mistaken for poison ivy, has five leaflets
radiating from one point of attachment.

Poison ivy can be found in one of three forms; as an erect woody
shrub, a trailing shrub running along the ground, or a woody vine. The
vine is usually seen growing on trees or other objects for support. It
has aerial roots along the stem that give it the appearance of a
"fuzzy rope." Yellowish-green flowers occur in compact clusters in
leaf axils, and are produced in June or July. The waxy, berry-like
fruit is grayish-white, with distinct lines marking the outer surface,
and is about three-sixteenths of an inch in diameter.

Poison Ivy--Rhus radicans

Control

There are three methods that can be effective in eradicating poison
ivy in ornamental beds. They include hand pulling or grubbing;
severing the vine and then treating the regrowth with an herbicide; or
applying an herbicide to individual leaflets.

Hand pulling is most successful when the soil is moist. The roots can
be dug and pulled out in long pieces. Care should be taken to remove
the entire root because the plant can resprout from sections of root
left in the ground. Avoid skin contact by wearing gloves while you
work and washing clothing and gloves immediately after. The washing
machine should be rinsed thoroughly afterward to eliminate the
possibility of contaminating other clothing.

Vines growing on trees can be difficult to pull out of the ground
because their roots may be entangled with the tree's roots. Sever the
vine at the base and carefully pull it out of the tree. Glyphosate
(eg., Roundup or Ortho's Kleeraway Grass & Weed Killer), a
non-selective, translocated herbicide, can be applied to the new
shoots that will soon emerge from the base of the old plant. This
herbicide is most effective if applied to actively growing foliage two
weeks on either side of full bloom, in early summer.

Another herbicide that may be used is triclopyr (eg., Ortho's
Brush-B-Gon Poison Ivy Killer). Poison ivy is difficult to control
even with herbicides. Neither glyphosate nor triclopyr will provide
complete control from a single application, and repeat applications to
treat regrowth may be necessary. Other herbicide brands or
formulations may be found at your local garden center. Be sure to read
the label to ensure that poison ivy is listed on the label, then
follow the manufacturer's directions.

Poison Ivy--Rhus radicans

When poison ivy is found in the midst of your prized ornamental
plants, special care should be taken to eliminate it. Paint the
individual leaflets with a non-selective herbicide like glyphosate to
avoid harming desirable plants.

Things to Know

The blistering rash caused by poison ivy is the direct result of
contact with the oily toxicant, known as "urushiol." Urushiol is found
in resin ducts within the plant's phloem. These ducts are found
throughout the plant, including the roots, stems, bark, leaflets and
certain flower parts. The plant has to be crushed, broken, or in some
way injured to release the resin. The injury may be something as
little as an insect chewing on the plant.

Once urushiol is released, it can find its way to your skin by direct
contact with the plant and then spread by touching other parts of the
body. Because the sticky, oily substance is easily transmitted, there
are indirect ways to contact it, for instance, from the fur of the
family pet, garden tools, garden gloves, clothing, golf balls or other
objects that have come in contact with an injured plant. Contrary to
popular belief, the rash from poison ivy cannot be transmitted from
touching the oozing blisters.

If you know you have contacted poison ivy, wash the area as soon as
possible with soap and cool water. Warm water may cause the resin to
penetrate the skin faster. Because urushiol can penetrate in a matter
of minutes, you may still get a rash, but at least you have contained
the infected area. A visible reaction, redness and swelling may be
apparent within 12 to 24 hours. Contact your family physician or
pharmacist for recommendations for effective non-prescription
medication.

One additional caution is that people can contract a rash by exposure
to smoke of burning poison ivy; be careful not to burn wood with the
poison ivy vine attached to it. Take extreme caution to avoid inhaling
smoke or contact of smoke with skin and clothing.

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